山玉兰花粉离体萌发和花粉管生长特性的研究

山玉兰(Magnolia delavayi)是木兰科木兰属的常绿乔木或大型灌木,是重要的园林造景、庭院绿化素材,也是重要的育种资源。山玉兰花粉的研究对其杂交育种的成败具有重要影响,但目前尚未见其花粉活力的相关报道。该研究以新鲜的山玉兰花粉为对象,采用悬滴培养法分析了温度、光照以及培养液的蔗糖和硼酸浓度对山玉兰花粉萌发的影响。结果表明:(1)山玉兰花粉萌发时,最适宜的温度为27℃。(2)光暗条件下,山玉兰花粉以浓度为5%的蔗糖培养效果最佳,其萌发率在16%以上;而硼酸浓度则以0.001%的培养效果最佳。(3)蔗糖与硼酸共同作用可有效促进花粉萌发和花粉管生长。其中,在光照条件下,以5.0%蔗糖+0.001%硼酸为最适宜的培养液,花粉萌发率达41.27%,花粉管长达281.49μm;而在黑暗条件下,则以5.0%蔗糖+0.01%硼酸为最适宜的培养液,花粉萌发率达45.71%,花粉管长达254.00μm。该研究结果为进一步开展人工辅助授粉、发掘山玉兰的种质资源工作奠定了基础。

Characteristics of pollen germination and pollen tube growth of Magnolia delavayi

Magnolia delavayi (Magnoliaceae, Magnolia) distributed in Yunnan, southwestern Sichuan and Guizhou.As an evergreen arbor or large shrub plant, M.delavayi plays a significant role in garden landscaping and courtyard greening, and is also an important breeding resource.There were report on the pollen germination of M.delavayi, which was the key factor to the success of the hybrid breeding.To investigate the optimal cultured conditions of pollen germination and pollen tube growth of M.delavayi, the hanging drop method were used to culture fresh pollen grains of M.delavayi in liquid culture mediums with different concentrations of sucrose, boric acid under distinct temperature and lightness gradients.The results were as follows: (1) The most suitable temperature of M.delavayi was 27 ℃.(2) Under light and dark condition, the pollen germination rate of more than 16%, when the best concentration of sugar culture was 5% and the best concentration of boric acid was 0.001%.(3) Combined action sucrose and boric acid could be effectively promoted the pollen germination and pollen tube growth.The optimum liquid culture medium for pollen germination and pollen tube growth of M.delavayi contained 5% sucrose + 0.001% boric acid under light, in which pollen germination rate was 41.27% and the length of pollen tube was 281.49 μm;the appropriate nutrient liquid included 5% sucrose + 0.01% boric acid with pollen germination rate reaching 45.71% and 254.00 μm of the pollen tube length under the dark condition.The results discovered in this study will be useful for further artificial breeding and exploring germplasm resources of M.delavayi.